Rotary well pump



Oct. -I'I7, 1967 J. w. cRoNlN, JR.. ETAL 3,347,169

ROTARY WELL PUMP Original Filed Jan. 5, 1965 VEQQ/ 5. 5w/lf@ INVENTORS,

0d. 17, 1967 y J. w. cRoNlN, JR., ETAL 3,347,169

ROTARY WELL PUMP original Filed Jan. 5, 1965 2 sheets-sheet a United States Patent O 3,347,169 ROTARY WELL PUMP John W. Cronin, Jr., La Mirada, and Verdi E. Boyer, San Gabriel, Calif., assignors, by mesne assignments, to Sargent Industries, Oil Well Equipment Division, Huntington Park, Calif., a corporation of Delaware Continuation of application Ser. No. 423,482, Jan. 5, 1965. This application Sept. 26, 1966, Ser. No. 582,170 1 Claim. (Cl. 103-117) This is a continuation of application Ser. No. 423,482 filed J an. 5, 1965, now abandoned.

This invention relates to well pumps and is particularly directed to improvements in rotary pumps which are placed down in the well and which are driven from a prime mover located at the surface.

Some wells produce quantities of sand or other formation material along with the well fluid in such quantities as to cause excessive wear from the working parts lof conventional well pumps. Rotary pumps of the so-called Moineau type have been used in oil wells producing excessive amounts of said because of the well known abiiity of such pumps to handle sandy or gritty materials. The rotor in such pumps has a helical -outer surface shaped in the manner of a corkscrew and the stator has corkscrew-like helicalchannels on its inside surface, While such Moineau pumps have been used successfully at the surface for many years, their use in oil wells has given rise to difficulties on lowering the pumps and installing it in position in the well,` and in maintaining the rotorA and stator in proper relationship in operation in the well.

Difficulties have been encountered in attempting to lower an assembled rotor and stator of the Moineau-type pump down into the well tubing on the end of a cable, the cable being later used for turning the rotor. Where the well fluid is viscous in character, the assembled unit of rotor and stator may not move readily downward through the viscous well fluid 'since the passage through the stator is blocked by the presence of the rotor and since the outer diameter of the stator assembly has only minimum clearance with the inside diameter of the well tubing. The cable does not afford any effective means of applying downward thrust to the assembled rotor and stator unit to move it through the viscous iiuid into position at the proper depth in the well tubing. Moreover, when torque is applied to the cable to cause the rotor to turn within the stator, the cable may tend to `shorten to some extent and lift the rotor rand stator from the properoperating depth. It is an important object of this invention to provide a novel form of lock for automatically anchoring the'stator at the proper elevation in the wall tubing.

It'is another important object of this invention to provide novel apparatus for vlowering the rotor and stator in the well tubing on a cable, the rotor being spaced axially from the stator during the lowering operation in order that the assembly may drop through viscous fluid, the rotor subsequently being lowered into operating position within the stator after theassembly has reached proper depth within the well tubing.

Another object is to provide a telescoping drive assembly so that any changes in the length of the cable when rotating under torque load will not adversely affect the axial position of the rotor within the stator.

Other and more detailed objects and advantages will appear hereinafter.

In the drawings:

FIGURE 1 is a schematic side elevation showing a well tubing extending downward into a well and showing certain mechanism at the well head.

FIGURE 2 is a sectional side elevation showing parts at the lower end of FIGURE 1 on an enlarged scale, and

3,347,l69 Patented (ict. 17, 1967 ICC showing the parts in position while being lowered into the hole.

FIGURE 3a is a view similar to FIGURE 2 showing the parts in operating position.

FIGURE 3b is a continuation of the lower end of FIG- URE 3a.

FIGURE 4 is a sectional detail taken substantially on the lines 4 4 as shown 4in FIGURE 2.

FIGURE 5 is a transverse sectional plan View taken substantially on the lines 5--5, as shown in FIGURE 3b.

FIGURE 6 is a side elevation partly broken away showing the extreme lower-end portion of the stator assembly.

FIGURE 7 is a longitudinal sectional View of the telescoping drive assembly.

FIGURE 8 is a transverse section taken substantially on lines 8--8 as shown in FIGURE 7.

Referring to the drawings, the sectional well tubing 10 extends downward into a well 11 from a well-head structure generally designated 12. A lateral branch pipe 13 above the well head 12 communicates with the interior of the tubing 10. A wire ycable 15 extends downward through the interior of the tubing string 1t), and this cable is preferably provided with both right-hand lay and left-hand lay components. The rotary pump `assembly generally designated 16 having a Moineau-type rotor 17 and stator 18 is connected to the lower end of the stranded cable 15 by means of the telescoping drive assembly 19. Cooperating parts 20 and 2.1 are provided on the lower end of the tubing string 1t) and the lower end of the stator assembly for locking the stator assembly in position. In the general plan of operation, the pump assembly 16 and the telescoping drive assembly 19 are lowered down through the interior of the tubing string 10 on the lower end of the cable 15 until the parts 20 and 21 are interengaged and until continued downward movement of the cable 15 brings the rotor 17 into position within the stator 18. The stranded cable 15 is then rotated at the surface to cause the telescoping drive assembly to turn the rotor 17 within the stator 1S, and thereby raise the well fluid up through the tubing string 10 and to flow out through Ithe lateral pipe 4'13.

FIGURE 2 shows the position of the rotor 17 and stator 18 while the parts are being lowered into position through the tubing string 10. The tting 25 at the lower end of the telescoping drive assembly 19 is connected by coupling 26 and shaft 27 to the upper end of the corkscrew-like rotor 17. Relatively loose left-hand threads 28 also connect the upper end of the rotor to the sectional tubular sleeve 29. The stator 18 with its corkscrew-like internal helical channels 18a is fixed within one of the sections -of this sleeve 29. A tubular coupling 30 connects the lower end of the sleeve 29 to the tubular locking sleeve 20.

' It will be observed that the position of the rotor 17 and stator 18 as shown in FIGURE 2 is such that the lower end of the rotor 17 is placed above the upper end of the stator 18 when the pump assembly is being lowered into the well tubing 10. In this way the central unblocked opening through the stator 18 and through the sleeve parts 2t), 29 and 30 permits viscous fluid to flow through the interior of the stator 18 and out through the lateral window 32 in the upper end of the sleeve 29 as the pump assembly is being lowered into position. If the rotor 17 were to be in position within the stator 18 during this lowering movement, viscous well fluid would offer resistance to lowering of the pump assembly 16 into position within the tubing 10. The flexible cable 15 does not afford any means of applying effective downward thrust, and therefore it might take some time for the pump assembly 16 to settle through viscous fluid in the well tubing. The axial separation of the rotor 17 and 3 stator 18 during the lowering movement overcomes this diiiiculty.

The projections 35 at the lower end of the locking sleeve 2t) cooperate with the shape of the curved internal plates or lugs 21 at the lower end of the tubing string so that automatic engagement is achieved. The plates 21 are held in position by means of threaded fastenings 36 mounted on the hollow body 37 at the lower end of the sectional tubing string 11). The inclined surfaces 38 on the i parts 21 and the inclined surfaces 39 on the projections 35 cause relative turning movement between the parts so that the projections 35 may pass downward through the clearance spaces between the parts 21 to reach the position shown in FIGURE 3b. Subsequent turning movement of the cable 15 in the direction for proper rotation of the rotor 17 serves to turn the projections 35 to the locking position shown in FIGURE 5, in which each of them engages one of the boltheads of afastening assembly 36.

In' this angular position, axial separation of the parts 20 t and 37 is prevented because of the shoulders 40 which underlie the plates 21. Packing rings 41 are provided to prevent leakage between these parts 20 and 37.

When rotation of the sectional sleeve 29 is arrested by engagement of the parts with the boltheads of fastenings 36 as shown in FIGURE 5, the lefthand threads 28 are disengaged by continued rotation of the cable 15. The cable is then lowered for an additional distance to position therotor 17 in operating position within the stator i8, as shown in FIGURE 3b. Continued rotation of the cable 15 turns the rotor 17 within the stator 18 and causes the pump assembly to lift well fluid upward through the tubing string 1t). The rotation of the cable 15 may be accomplished at the surface by means of a pulley 42 tixed to the cable 15 and driven by a belt 43 from a motor 44.

Any tendency of the rotor 17 to be lifted by shortening of the overall length of the rotating cable is eliminated by the telescoping drive assembly 19. This assembly 19 includes the shell member 46 which is connected by threads 47 to the fitting 48 at the lower end of the cable 15. The shell member 46 includes a portion 49 having a non-circular bore 50 which may be hexagonal. A noncircular stem 52 of similar cross-section is slidablyv mounted within the bore 50 to transmit torque. An enlarged cap 53 on the stem prevents disassembly of the parts. The lower end of the sliding stem 52 is connected by threads 54 to the member 25. In operation, the surface 55 turns against the surface 56.

When it is desired to withdraw the pump assembly 16 from the tubing string 10, the cable 15 is lifted vertically. This serves first to retract the rotor 17 from the 'interior of the stator 18 and then when the threaded parts 28 meet in end-to-end engagement, additional tension springs shoulders inward fromengagement under plates 21. The entire pump assembly may then be withdrawn from the well on the end of the cable.

Having fully described our invention, it is to be understood that we are not to be limited to the details herein set forth, but that our invention is of the full scope of 60 the appended claim.

We claim:

A cable supported and operated rotary pump for use when anchored within the lower end of a tubing string disposed in a well bore, said rotary pump comprising:

(a) latch means within the lower end of the tubing string including at least a pair of arcuate internal ribs separated by axially directed guide channels, the upper ends of said ribs forming helical cam surfaces directed into said channels, the lower ends of said ribs forming latching abutments;

(b) a pump stator having an undulated internal surf race;

(c) a sleeve extending downward from said stator and forming an entrance passage;

(d) latch ngers extending from said sleeve, engageable with said cam surfaces, dimensioned to be received in said channels, and rotatable into latching engagement with said abutments;

(e) a sleeve having an outlet port and extending upwardly from said stator, to form an outlet passage, said sleeve having an internal rotary operable separable connector element at its upper end;

(f) a rotor having an external helical surface for cooperation with said stator;

(g) a stern fixed to said rotorand extending upwardly in said outlet passage and through said connector element when said rotor is received in said stator;

(h) an external separable connector element'disposed at the lower end of said stem, said connector elements being mutually engageable to secure said rotor in axially spaced relation to said stator thereby to permit free tlow of fluid through said passages and stator;

(i) and means attaching said stem to said supporting and operating cable;

(j) said lingers being engageable with said abutmentS when said stator is lowered to the bottom of said tubing string and said cable is rotated in a direction intended t o cause said rotor and stator to pumpy uid thereby to secure said stator;

(k) and said separable connecting elements being dis engageable, on rotation of said Cable in a direction intended to cause said stator and rotor to pump fluid, to permitlowering of said rotor -into said stator.

References Cited UNITED STATES PATENTS 1,036,824 8/1912 Gable 103-119 1,980,985 11/1934 Deming 103-119 2,267,459 12/ 1941 Hait 103--117 2,346,426 4/1944 Hait 103-117 2,379,944 7/ 1945 Willmott 64-2 2,464,011 3/1949 Wade 103-119 2,586,360 2/1952 Mall 64-23 2,684,639 7/1954 Sutton 103-181 2,739,650 3/1956 Hill 103-117 2,898,087 S/1959 Clark 175-99 DONLEY I. STOCKING, Primary Examiner.

W, J. GOODLIN, Assistant Examiner. 

